Display device

ABSTRACT

A display device includes a display panel including a display area including: a stretchable display area at which the display panel is stretchable, disposed at an outer edge of the display device, and a normal display area having flexibility less than that of the stretchable display area, the normal display area disposed further from the outer edge of the display device than the stretchable display area; a cover window disposed on the display panel, including a peripheral portion and a central portion which is disposed further from the outer edge of the display device than the peripheral portion; and a vibration member disposing the normal display area having the flexibility less than that of the stretchable display area between the central portion of the cover window and the vibration member along a thickness direction of the display device.

This application is a divisional application of U.S. patent applicationSer. No. 16/156,075 filed on Oct. 10, 2018, which claims priority toKorean Patent Application No. 10-2018-0050526, filed on May 2, 2018, andall the benefits accruing therefrom under 35 U.S.C. § 119, the contentsof which in their entirety are herein incorporated by reference.

BACKGROUND 1. Field

The invention relates to a display device.

2. Description of the Related Art

The importance of a display device has increased with the development ofmultimedia. Accordingly, various types of display devices such as aliquid crystal display (“LCD”) and an organic light emitting display(“OLED”) have been used.

Among display devices, a liquid crystal display device, which is one ofthe most widely used flat panel display devices, includes two substratesincluding electric field generating electrodes such as a pixel electrodeand a common electrode, and a liquid crystal layer disposedtherebetween. In the liquid crystal display device, a voltage is appliedto the electric field generating electrodes to form an electric field inthe liquid crystal layer, so that the alignment of liquid crystalmolecules in the liquid crystal layer is determined, and thepolarization of incident light is controlled, thereby displaying animage.

Further, among display devices, an organic light emitting display devicedisplays an image using an organic light emitting element generatinglight by recombination of electrons and holes. The organic lightemitting display device is advantageous in that it has a relatively highresponse speed, high luminance and wide viewing angle, and is driven byrelatively low power consumption.

Interests in display devices for which a shape thereof is deformablehave increased with the development of display-related technologies.Thus, research and development on flexible display devices that can bedeformed such as by being rolled or folded and stretchable displays thatcan be deformed such as by being extended are actively under way.

SUMMARY

One or more embodiment of the invention provides a display device havingimproved sound transfer capability through vibration.

One of more of another embodiment of the invention provides a displaydevice having a relatively narrow bezel.

According to one or more embodiment of the invention, there is provideda display device, including: a display panel including a display area atwhich an image is displayed, the display area including: a stretchabledisplay area at which the display panel is stretchable, disposed at anouter edge of the display device, and a normal display area havingflexibility less than that of the stretchable display area, the normaldisplay area disposed further from the outer edge of the display devicethan the stretchable display area; a cover window disposed on thedisplay panel, including a peripheral portion and a central portionwhich is disposed further from the outer edge of the display device thanthe peripheral portion; and a vibration member which transfers soundthrough vibration, the vibration member disposing the normal displayarea having the flexibility less than that of the stretchable displayarea between the central portion of the cover window and the vibrationmember along a thickness direction of the display device.

The peripheral portion may overlap the stretchable display area.

The stretchable display area may include an island provided in pluralityspaced apart from each other, and a bridge provided in pluralityrespectively connecting the plurality of islands to each other, thebridge being stretchable.

The stretchable display area of the display panel may further include adisplay unit with which the image is generated, the display unitincluding an organic light emitting diode, where the display unitincluding the organic light emitting diode is disposed on the island ofthe stretchable display area.

The stretchable display area of the display panel may further include afirst wiring and a second wiring disposed in different layers of thedisplay panel and each electrically connected to the display unit.

The bridge which is stretchable may have a serpentine shape extendedbetween islands connected to each other by the bridge, and each of thefirst wiring and the second wiring: may be connected to both displayunits respectively disposed on the islands connected to each other bythe bridge which is stretchable, and may have a serpentine shapecorresponding to that of the bridge to be stretchable together with thebridge.

The display device may further include: a bracket in which the vibrationmember and the display panel are accommodated, where the bracket isattached to the peripheral portion of the cover window and disposes thedisplay panel and the vibration member between the bracket and the coverwindow.

The display device may further include: a cover panel which radiatesheat from or absorbs an impact to the display panel, disposed betweenthe display panel and the bracket.

The display device may further include: an adhesive layer disposedbetween the bracket and the cover panel.

The vibration member may include a piezo material.

The peripheral portion may extend further than the normal display areaof the display panel, the extended peripheral portion being bent with atleast one curvature in the thickness direction of the display device.

The stretchable display area may extend further than the central portionof the cover window to be bent corresponding to the curvature of theperipheral portion of the cover window.

The central portion may have flexibility less than that of theperipheral portion of the cover window.

Within the cover window, a material of the central portion havingflexibility less than that of the peripheral portion may include glass,and a material of the peripheral portion having flexibility greater thanthat of the central portion may include at least one selected fromplastic, silicone and a polymer material having elasticity.

According to one or more of another embodiment of the invention, thereis provided a display device, including: a cover window through which animage is displayed, including a central portion and a peripheral portionwhich is disposed closer to an outer edge of the display device than thecentral portion; a first display panel with which an image is displayed,including: a first dummy area corresponding to the central portion ofthe cover window, and a stretchable display area at which the image ofthe first display panel is displayed and at which the first displaypanel is flexible, the stretchable display area disposed closer to theouter edge of the display device than the first dummy area; and a seconddisplay panel with which an image is displayed, including: a normaldisplay area corresponding to the first dummy area of the first displaypanel and at which the image of the second display panel is displayed,and a second dummy area disposed corresponding to the stretchabledisplay area of the first display panel, the second dummy area disposedcloser to the outer edge of the display device than the normal displayarea, where the flexibility of the stretchable display area of the firstdisplay panel is greater than that of the normal display area of thesecond display panel, and flexibility of the peripheral portion of thecover window is greater than that of the central portion of the coverwindow.

The second dummy area may have optical transparency and may include anelastic material.

The second dummy area, the stretchable display area, and the peripheralportion may overlap one another.

The first dummy area may have substantially a same planar area as thenormal display area.

The stretchable display area of the first display panel may include: anisland provided in plurality spaced apart from each other, and a bridgeprovided in plurality respectively connecting the plurality of islandsto each other, the bridge being stretchable.

The stretchable display area of the first display panel may furtherinclude a display unit with which the image of the first display panelis generated, the display unit including an organic light emittingdiode, where the display unit including the organic light emitting diodeis disposed on the island of the stretchable display area.

Therefore, within one or more embodiment of the display device, callquality and quality of sound transferred through vibration may beimproved.

However, features of the invention are not restricted to the one setforth herein. The above and other features of the invention will becomemore apparent to one of ordinary skill in the art to which the inventionpertains by referencing the detailed description of the invention givenbelow.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other features of the invention will become more apparentby describing in detail exemplary embodiments thereof with reference tothe attached drawings, in which:

FIG. 1 is a perspective view of an embodiment of a display deviceaccording to the invention;

FIG. 2 is a cross-sectional view taken along line I-I′ in FIG. 1;

FIG. 3 is a partial top plan view of an embodiment of a display panel ofa display device according to the invention;

FIG. 4 is an enlarged top plan view of portion “A” in FIG. 3;

FIG. 5 is a cross-sectional view taken along line II-II′ in FIG. 4;

FIG. 6 is a partial top plan view of an embodiment of a cover window ofa display device according to the invention;

FIG. 7 is a partial top plan view of an embodiment of a display unit ofa display device according the invention;

FIG. 8 is a partial top plan view of a modified embodiment of a displayunit of a display device according to the invention;

FIG. 9 is a cross-sectional view of another embodiment of a displaydevice according to the invention;

FIG. 10 is a cross-sectional view of a modified embodiment of displaydevice according to the invention;

FIG. 11 is a cross-sectional view of still another embodiment of adisplay device according to the invention; and

FIG. 12 is a cross-sectional view of yet another embodiment of a displaydevice according to the invention.

DETAILED DESCRIPTION

The advantages and features of the invention and methods for achievingthe advantages and features will be apparent by referring to theembodiments to be described in detail with reference to the accompanyingdrawings. However, the invention is not limited to the embodimentsdisclosed hereinafter, but can be implemented in diverse forms. Thematters defined in the description, such as the detailed constructionand elements, are nothing but specific details provided to assist thoseof ordinary skill in the art in a comprehensive understanding of theinvention, and the invention is only defined within the scope of theappended claims.

Where an element is described as being related to another element suchas being “on” another element or “located on” a different layer or alayer, includes both a case where an element is located directly onanother element or a layer and a case where an element is located onanother element via another layer or still another element. In contrast,where an element is described as being is related to another elementsuch as being “directly on” another element or “located directly on” adifferent layer or a layer, indicates a case where an element is locatedon another element or a layer with no intervening element or layertherebetween. In the entire description of the invention, the samedrawing reference numerals are used for the same elements across variousfigures.

Although the terms “first,” “second” and so forth are used to describediverse constituent elements, such constituent elements are not limitedby the terms. The terms are used only to discriminate a constituentelement from other constituent elements. Accordingly, in the followingdescription, a first constituent element may be a second constituentelement.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting. As used herein, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms, including “at least one,” unless the content clearly indicatesotherwise. “At least one” is not to be construed as limiting “a” or“an.” “Or” means “and/or.” As used herein, the term “and/or” includesany and all combinations of one or more of the associated listed items.It will be further understood that the terms “comprises” and/or“comprising,” or “includes” and/or “including” when used in thisspecification, specify the presence of stated features, regions,integers, steps, operations, elements, and/or components, but do notpreclude the presence or addition of one or more other features,regions, integers, steps, operations, elements, components, and/orgroups thereof.

Furthermore, relative terms, such as “lower” or “bottom” and “upper” or“top,” may be used herein to describe one element's relationship toanother element as illustrated in the Figures. It will be understoodthat relative terms are intended to encompass different orientations ofthe device in addition to the orientation depicted in the Figures. Forexample, if the device in one of the figures is turned over, elementsdescribed as being on the “lower” side of other elements would then beoriented on “upper” sides of the other elements. The exemplary term“lower,” can therefore, encompasses both an orientation of “lower” and“upper,” depending on the particular orientation of the figure.Similarly, if the device in one of the figures is turned over, elementsdescribed as “below” or “beneath” other elements would then be oriented“above” the other elements. The exemplary terms “below” or “beneath”can, therefore, encompass both an orientation of above and below.

“About” or “approximately” as used herein is inclusive of the statedvalue and means within an acceptable range of deviation for theparticular value as determined by one of ordinary skill in the art,considering the measurement in question and the error associated withmeasurement of the particular quantity (i.e., the limitations of themeasurement system). For example, “about” can mean within one or morestandard deviations, or within ±30%, 20%, 10% or 5% of the stated value.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms, such as those defined in commonly useddictionaries, should be interpreted as having a meaning that isconsistent with their meaning in the context of the relevant art and thepresent disclosure, and will not be interpreted in an idealized oroverly formal sense unless expressly so defined herein.

Exemplary embodiments are described herein with reference to crosssection illustrations that are schematic illustrations of idealizedembodiments. As such, variations from the shapes of the illustrations asa result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments described herein should not beconstrued as limited to the particular shapes of regions as illustratedherein but are to include deviations in shapes that result, for example,from manufacturing. For example, a region illustrated or described asflat may, typically, have rough and/or nonlinear features. Moreover,sharp angles that are illustrated may be rounded. Thus, the regionsillustrated in the figures are schematic in nature and their shapes arenot intended to illustrate the precise shape of a region and are notintended to limit the scope of the present claims.

Hereinafter, embodiments of the invention will be described withreference to the attached drawings.

FIG. 1 is a perspective view of an embodiment of a display deviceaccording to the invention. FIG. 2 is a cross-sectional view taken alongline I-I′ in FIG. 1.

Referring to FIGS. 1 and 2, a display device according to an embodimentof the invention includes a display panel PA, a cover window CW disposedon the display panel PA, and a vibration member 50 disposed under thedisplay panel PA.

The display device according to an embodiment of the invention mayfurther include a bracket BC and a cover panel 500. The display deviceand components thereof may be disposed in a plane defined by first andsecond directions which cross each other. A thickness of the displaydevice and/or components thereof is disposed along a third directionwhich crosses each of the first and second directions. In FIG. 2, avertical direction may represent the third (thickness) direction, whilea horizontal direction may represent the first and/or second directions.

A bezel of the display device is viewable along the thickness direction,e.g., vertically top-down in FIG. 2, in a top plan view. A size of thebezel is taken along the first and/or second directions, e.g., thehorizontal direction in FIG. 2.

Referring to FIG. 1, the bracket BC may be coupled with the cover windowCW to form an outer appearance of the display device. That is, thebracket BC and the cover window CW may form outermost surfaces of thedisplay device.

The bracket BC may accommodate therein various components of the displaydevice to be described later. For this purpose, the bracket BC mayinclude a bottom portion BC_B and a side wall BC_S. The side wall BC_Smay extend from an outer edge of the bottom portion BC_B at one or moresides of the display device.

In an embodiment, the side wall BC_S of the bracket BC may be engagedwith the cover window CW to be coupled thereto and form the outerappearance of the display device. For this purpose, a first adhesivelayer AD1 may be interposed between a distal end of the side wall BC_Sof the bracket BC and the cover window CW.

In an embodiment, the first adhesive layer AD1 may be a heat-activatedtape. In this case, when the first adhesive layer AD1 is heated to aspecific temperature, the adhesive performance of the first adhesivelayer AD1 increases, and thus the side wall BC_S of the bracket BC maybe attached to the cover window CW.

The first adhesive layer AD1 may be considered a portion of the bracketBC or the cover window CW. The first adhesive layer AD1 may form aportion of the outer appearance of the display device, along with thebracket BC and the cover window CW. In this way, when the side wall BC_Sof the bracket BC is directly attached to the cover window CW, aseparate member does not overlap or block the upper surface of the coverwindow CW in the top plan view. Thus, a display device having no bezelor having a minimal (e.g., very narrow) bezel can be realized.

In an embodiment, the first adhesive layer AD1 may be in contact withthe display panel PA. Specifically, the first adhesive layer AD1 may bein contact with a component of the display panel PA in a non-displayarea NDA of the display panel PA. Details of the non-display area NDAwill be described later.

In an embodiment, the bottom portion BC_B of the bracket BC may beprovided with a mounting portion 55. The mounting portion 55 may have agroove shape recessed from the upper surface of the bottom portion BC_Bby a predetermined distance along the thickness direction (e.g.,vertical direction in FIG. 2). A vibration member 50 may be mounted inthe mounting portion 55.

In an embodiment, a fixing layer 400 may be disposed on the bottom ofthe mounting portion 55. The fixing layer 400 has adhesive performanceto fix the vibration member 50 to the mounting portion 55. However, inanother embodiment, the fixing layer 400 may be omitted and thevibration member 50 may be fixed to the mounting portion by a fixingelement different from the fixing layer 400 or solely by a coupling ofthe vibration member 50 and the mounting portion 55 to each other.

The vibration member 50 can transfer sound therefrom through vibration.That is, for this purpose, the vibration member 50 may include avibration element that generates vibration and provides the vibrationsuch as to outside the vibration member 50. In an embodiment, thevibration element may include a piezo material, for example,polyvinylidene fluoride (“PVDF”) or lead zirconium titanate ceramic(“PZT”), which vibrates under a constant electric field.

Since the vibration member 50 transfers sound through vibration, thevibration generated in the vibration member 50 and transferred to a useris maximized by minimizing a loss of the vibration. As will be describedlater, each of the display panel PA and the cover window CW may have anadvantageous structure to which vibration is transferred from thevibration member 50.

In an embodiment, the vibration member 50 may be disposed of formedextended through the cover panel 500. Specifically, at least onethrough-hole (not shown) may be defined or formed in the cover panel500, and the vibration member 50 may be inserted into the through-hole.The through-hole may penetrate an entirety of the thickness of the coverpanel 500, without being limited thereto.

The cover panel 500 may be disposed or formed on the bracket BC, and maycover the back surface of the display panel PA. In the top plan view, anentirety of the back surface of the display panel PA may be overlappedby the cover panel 500 to be covered thereby.

In an embodiment, the cover panel 500 can perform a heat radiationfunction and/or a shock absorption function.

Although it is shown in FIG. 2 that the cover panel 500 is a singlelayer, the invention is not limited thereto. That is, in anotherembodiment, the cover panel 500 may include a plurality of functionallayers which are stacked and/or coupled to each other.

In an embodiment, the cover panel 500 may include or be formed of ametal material such as gold, silver or copper, a material includinggraphite, or a material including carbon nanotubes, in order to performthe heat radiation function.

In an embodiment, the cover panel 500 can serve to reduce or effectivelyprevent damage to the display device from an external impact appliedthereto, by absorbing the external impact. For this purpose, the coverpanel 500 may include or be made of an elastic material such as apolyurethane resin or a polyethylene resin.

A light-blocking adhesive layer 380 may be disposed on the cover panel500, such as at a side of the cover panel 500 closest to a viewing sideof the display device. The light-blocking adhesive layer 380 has anadhesive performance, and may be disposed between the display panel PAand the cover panel 500. The light-blocking adhesive layer 380 disposedbetween the display panel PA and the cover panel 500 may attach thedisplay panel PA to the cover panel 500. The light-blocking adhesivelayer 380 can serve to absorb external light incident thereto, such asexternal light transmitted through the cover window CW to thelight-blocking adhesive layer 380. For this purpose, the light-blockingadhesive layer 380 may include a colored pigment, particularly, a blackpigment.

The display panel PA may be disposed on the light-blocking adhesivelayer 380, at a side of the light-blocking adhesive layer 380 closes tothe viewing side of the display device. Details of the display panel PAwill be described with reference to FIG. 3.

FIG. 3 is a partial top plan view of an embodiment of a display deviceaccording to an embodiment of the present invention. FIG. 3 is a topplan view of the display panel PA indicated in FIGS. 1 and 2 accordingto the invention. The cover window CW and the bracket BC of the displaydevice in FIGS. 1 and 2 are omitted for convenience of explanation.

Referring to FIG. 3, the display panel PA may include a display area DAand a non-display area NDA which is disposed outside the display area DAin the top plan view. In an embodiment, the display panel PA may includea base substrate common to each of the display area DA and thenon-display area NDA. The base substrate of the display panel PA mayinclude an insulating (base) substrate on which various layers of thedisplay panel PA are disposed to define a pixel, a display unit, alight-emitting area, a stretchable area, a non-stretchable (e.g.,normal) area, etc.

The non-display area NDA is disposed outside the display area DA, and isdefined as an area where an image is not displayed. In an embodiment,the non-display area NDA may be disposed to surround the display areaDA. Although it is shown in FIG. 3 that the non-display area NDAsurrounds the display area DA, the invention is not limited thereto. Inanother embodiment, the non-display area NDA may be disposed adjacent toonly one side of the display area DA, or may be disposed adjacent tomore than one side of the display area DA.

In an embodiment, a plurality of pads or terminal (not shown) may bedisposed in the non-display area NDA, such as on the base substrate ofthe display panel PA. The plurality of pads of the display panel PA maybe connected to components or layers within the display panel PA, suchas those at the display area DA of the display panel PA. The pluralityof pads of the display panel PA may also be connected to an elementexternal to the display panel PA, such as a printed circuit board (notshown). Data signals, control/driving signals and/or power signals fordriving the display device to display an image may be provided to andfrom the external component, through the plurality of pads, from and tothe display panel PA, respectively.

The display area DA may be disposed inside the non-display area NDA. Thedisplay area DA is an area at which an image is displayed, and mayinclude at least one pixel. A pixel is a basic structure or element forgenerating and displaying the image. A plurality of pixels may bedisposed within the display area DA. The plurality of pads at thenon-display area NDA may be connected to pixels at the display area DAthereof. In an embodiment, the signals described above may be providedfrom the component external to the display panel PA and to the pixelsvia the plurality of pads, to display the image.

In an embodiment, the display area DA may include a normal (e.g., lessflexible or stretchable) display area NA and a stretchable (e.g., moreflexible or stretchable) display area STA. Each of the less flexiblenormal display area NA and the more flexible stretchable display areaSTA may be disposed in a same plane as each other, as illustrated inFIG. 2.

The normal display area NA and the stretchable display area STA are thesame as each other in the respect that each includes at least one pixelfor generating and displaying an image. That is, an image may be displayat each of the normal display area NA and the stretchable display areaSTA. In an embodiment, each of the normal display area NA and thestretchable display area STA may include on the base substrate of thedisplay panel PA, a same collection of layers constituting the pixelsuch as a display unit, a switching element, a light-emitting area, etc.However, the physical structure of portions a base substrate disposed inthe display area DA of the display panel PA may be somewhat differentfrom each other.

Specifically, the stretchable display area STA may have greaterflexibility than the normal display area NA. In this specification the“having greater flexibility” may mean that the extent of stretching isgreater when the same force is applied. In other words, if thestretchable display area STA and the normal display area NA are deformedby the same force, such as being pulled in a direction, the stretchabledisplay area STA may be extended further relative to the normal displayarea NA.

In addition, the stretchable display area STA may have elasticity. Thatis, even if the stretchable display area STA is extended by apredetermined distance by applying an external force to the stretchabledisplay area STA, the stretchable display area STA may be restored to anoriginal shape when the applied external force is removed.

In an embodiment, the difference in flexibility between the stretchabledisplay area STA and the normal display area NA may be attributed to thestructural characteristics of a (base) substrate disposed in thestretchable display area STA (hereinafter referred to as a stretchablesubstrate STS) as compared to the structural characteristics of a basesubstrate not disposed in the stretchable display area STA.

FIG. 4 is an enlarged view of portion “A” in FIG. 3.

Referring to FIG. 4, the stretchable display area STA may include astretchable substrate STS.

The stretchable substrate STS may be an insulating (base) substratehaving a structure as described below.

The stretchable substrate STS may include a plurality of islands 101spaced apart from each other and a plurality of bridges 103 whichconnect the plurality of islands 101 to each other. In an embodiment,the plurality of the islands 101 and the plurality of bridges 103 may beintegrally formed. In an embodiment, the structure for forming thestretchable substrate STS may include or be formed of an organicmaterial having elasticity and ductility. An example of the organicmaterial may include polyimide (“PI”). However, this is illustrative,and the material of the stretchable substrate STS is not limitedthereto, any of a number of materials having elasticity or ductility maybe used as the material of the stretchable substrate STS.

In an embodiment, a display unit 600 may be disposed on the island 101.

Each of the plurality of bridges 103 may have a non-linear shape such asa serpentine shape or a zigzag shape in a plan view, without beinglimited thereto. Thus, when an external force is applied to thestretchable substrate STS, the serpentine bridge 103 may be partiallystretched and extended.

In an embodiment, an external force may be applied along directionsforming the plane in which the stretchable substrate STS is disposed.Referring to FIG. 4, an external force may be applied along the pageview, e.g., in a direction vertical, horizontal and/or inclined. Sincethe island 101 and bridges 103 are arranged along the page view (e.g.,in the plane in which the stretchable substrate STS is disposed), theapplied external force may change a position of the island and/or thebridges 103 within the plane from an original position. Additionallyand/or alternatively, an external force may be applied along thethickness direction of the stretchable substrate STS, e.g., into thepage view of FIG. 4. Accordingly, a distance between the adjacentislands 101, taken along the plane directions and/or the thicknessdirection, may increase and decrease. Thus, the stretchable substrateSTS may have a two-dimensional and/or three-dimensional shape change.

Since empty spaces V are defined or formed among the plurality ofbridges 103 and the islands 101, the stretchable substrate STS may havea net pattern as a whole. The empty spaces V may be portions of thestretchable substrate STS at which the plurality of bridges 103 and theislands 101 are not disposed. Due to such a structure, the stretchablesubstrate STS may have relatively high flexibility. In an embodiment,the base substrate of the display panel PA may be exposed at the emptyspaces V formed among the plurality of bridges 103 and the islands 101.

A first wiring 610 and a second wiring 620 may be disposed on thestretchable substrate STS. The first wiring 610 and the second wiring620 may be connected to the display unit 600, and may transmit a signalto and/or from the display unit 600 for driving the display unit 600. Inan embodiment, the first wiring 610 and the second wiring 620 may bedisposed on the base substrate of the display panel PA at thestretchable substrate STS portion thereof.

In an embodiment, each of the first wiring 610 and the second wiring 620may include at least one selected from aluminum (Al)-based metalsincluding aluminum alloys, silver (Ag)-based metals including silveralloys, copper (Cu)-based metals including copper alloys, molybdenum(Mo)-based metals including molybdenum alloys, chromium (Cr), titanium(Ti) and tantalum (Ta).

In an embodiment, each of the first wiring 610 and the second wiring 620may have a shape corresponding to the shape of the bridge 103.Specifically, each of the first wiring 610 and the second wiring 620 mayat least partially overlap the bridge 103 in the top plan view, and mayhave a serpentine shape or a zigzag shape. When each of the first wiring610 and the second wiring 620 has a serpentine shape or a zigzag shape,each of the first wiring 610 and the second wiring 620 may be stretchedor contracted by a predetermined distance. That is, due to such asstructure, each of the first wiring 610 and the second wiring 620 mayhave flexibility or elasticity.

Accordingly, when the bridge 103 is stretched, each of the first wiring610 and the second wiring 620 may also be stretched at least partially,and stress to the wirings caused by the stretching is minimized due tothe flexibility or elasticity of the bridge 103. In other words, each ofthe first wiring 610 and the second wiring 620 having theabove-described structure can withstand the stress generated when thestretchable substrate STS is stretched, without breakage.

In an embodiment, the first wiring 610 may include or be made of thesame material as a gate electrode GE to be described later. In anembodiment of a method of manufacturing a display device, the firstwiring 610 may be formed simultaneously with the gate electrode GEand/or in the same process. In this case, the first wiring 610 is formedfrom or made of the same material as the gate electrode GE, and may bedisposed in the same layer as the gate electrode GE. That is, the firstwiring 610 and the gate electrode GE may be formed from a same materiallayer in manufacturing the display device.

In an embodiment, the second wiring 620 may include or be made of thesame material as a source electrode SE and/or a drain electrode DE to bedescribed later. In an embodiment of a method of manufacturing a displaydevice, the second wiring 620 may be formed simultaneously with thesource electrode SE and/or the drain electrode DE and/or in the sameprocess. In this case, the second wiring 620 is formed from or made ofthe same material as the source electrode SE and/or the drain electrodeDE, and may be disposed in the same layer as the source electrode SEand/or the drain electrode DE. That is, the second wiring 620 and thesource electrode SE and/or the drain electrode DE may be formed from asame material layer in manufacturing the display device.

In an embodiment, at least one organic light emitting diode OLED (referto FIG. 5) may be disposed in or on the display unit 600. The displayunit 600 may be driven to generate and/or emit light for displaying animage.

Details thereof will be described with reference to FIG. 5. FIG. 5 is across-sectional view taken along line II-II′ in FIG. 4.

Referring to FIG. 5, a buffer layer 210 may be disposed on the island101. The buffer layer 210 may planarize the surface of the island 101.In an embodiment, the buffer layer 210 may include any one of a siliconnitride (SiNx) film, a silicon oxide (SiO₂) film and a siliconoxynitride (SiOxNy) film. The buffer layer 210 may be omitted accordingto the type of the stretchable substrate STS and/or the processconditions thereof.

A semiconductor layer including a semiconductor pattern ACT may bedisposed on the buffer layer 210. The semiconductor layer will bedescribed with reference to the semiconductor pattern ACT. In anembodiment, the semiconductor pattern ACT may include or be formed ofany of a number of materials selected from polycrystalline silicon,monocrystalline silicon, low-temperature polycrystalline silicon,amorphous silicon, and oxide semiconductor, or may be formed bycombining two or more materials selected therefrom.

In an embodiment, the semiconductor pattern ACT may include a channelregion ACTa not doped with impurities, a source region ACTb doped withimpurities, and a drain region ACTc. The source region ACTb is disposedat a first side of the channel region ACTa, and is electricallyconnected to the source electrode SE to be described later. The drainregion ACTc is disposed at a second of the channel region ACTa whichopposes the first side thereof, and is electrically connected to thedrain electrode DE to be described later.

A first insulating layer 220 may be disposed on the semiconductor layerincluding the semiconductor pattern ACT. In an embodiment, the firstinsulating layer 220 may be a gate insulating layer. In an embodiment,the first insulating layer 220 may include or be formed of any of anumber of materials selected from inorganic materials such as siliconoxides (SiOx) and silicon nitrides (SiNx) and organic materials such asbenzocyclobutene (“BCB”), acrylic materials and polyimide, or may beformed by combining two or more materials selected therefrom.

A gate conductor including a gate electrode GE may be disposed on thefirst insulating layer 220. The gate electrode GE may overlap thesemiconductor pattern ACT. The gate conductor may include at least onematerial selected from aluminum (Al)-based metals including aluminumalloys, silver (Ag)-based metals including silver alloys, copper(Cu)-based metals including copper alloys, molybdenum (Mo)-based metalsincluding molybdenum alloys, chromium (Cr), titanium (Ti) and tantalum(Ta).

In an embodiment, the first wiring 610 may be electrically connected tothe gate electrode GE. Accordingly, the first wiring 610 may receive agate signal and transmit the gate signal to the gate electrode GE.

A second insulating layer 230 may be disposed on the gate conductorincluding the gate electrode GE. The second insulating layer 230 mayinclude or be formed of any one of a number of materials selected frominorganic materials such as silicon oxides (SiOx) and silicon nitrides(SiNx) and organic materials such as benzocyclobutene (“BCB”), acrylicmaterials and polyimide, or may be formed by combining two or morematerials selected therefrom.

A data conductor including a source electrode SE and a drain electrodeDE may be disposed on the second insulating layer 230. The sourceelectrode SE and the drain electrode DE are disposed on the secondinsulating layer 230 to be spaced apart from each other. The dataconductor may include at least one material selected from metals,alloys, metal nitrides, conductive metal oxides and transparentconductive materials. In an embodiment, the data conductor may have asingle-layer or multi-layer structure including nickel (Ni), cobalt(Co), titanium (Ti), silver (Ag), copper (Cu), molybdenum (Mo), aluminum(Al), beryllium (Be), niobium (Nb), gold (Au), iron (Fe), selenium (Se),tantalum (Ta), or the like. Further, an alloy formed by combining atleast one material selected from titanium (Ti), zirconium (Zr), tungsten(W), tantalum (Ta), niobium (Nb), platinum (Pt), hafnium (Hf), oxygen(O), and nitrogen (N) with the above metal may be used as the materialof the source electrode SE and the drain electrode DE.

The source electrode SE may be electrically connected to the secondwiring 620. The second wiring 620 may receive a data signal and transmitthe data signal to the source electrode SE.

The semiconductor pattern ACT, the gate electrode GE, the sourceelectrode SE and the drain electrode DE constitute a switching elementTR2. Although it is shown in FIG. 5 that the switching element TR2 is atop gate type switching element, the invention is not limited thereto.That is, the switching element TR2 may be a bottom gate type switchingelement.

A planarization layer 240 may be disposed on the data conductor. Theplanarization layer 240 can increase the luminous efficiency of a pixelelectrode 250 and an organic light emitting layer 270, which will bedescribed later, by removing a step difference between layers. In anembodiment, the planarization layer 240 may include an organic material.In an embodiment, for example, the planarization layer 240 may includebe made of at least one material selected from polyimide, polyacrylateand polysiloxane. In another embodiment, the planarization layer 240 mayinclude or be made of an inorganic material, or may include or be madeof a complex of an inorganic material and an organic material. A firstcontact hole CNT1 for exposing at least a part of the drain electrode DEmay be defined or formed in the planarization layer 240.

The pixel electrode 250 may be disposed on the planarization layer 240.The pixel electrode 250 may be electrically connected to the drainelectrode DE exposed by the first contact hole CNT1. That is, the pixelelectrode 250 may be an anode which is a hole injection electrode withinthe organic light emitting diode OLED. When the pixel electrode 250 isan anode, the pixel electrode 250 may include a material having arelatively high work function to facilitate hole injection. The pixelelectrode 250 may be a reflective electrode, a semi-transmissiveelectrode or a transmissive electrode. In an embodiment, the pixelelectrode 250 may include a reflective material. In an embodiment, thereflective material may include at least one material selected fromsilver (Ag), magnesium (Mg), chromium (Cr), gold (Au), platinum (Pt),nickel (Ni), copper (Cu), tungsten (W), aluminum (Al), aluminum-lithium(Al—Li), magnesium-indium (Mg—In) and magnesium-silver (Mg—Ag).

In an embodiment, the pixel electrode 250 may include or be formed of asingle-layer film, but the invention is not limited thereto. That is,the pixel electrode 250 may include or be formed of a multi-layer filmin which two or more materials are stacked or laminated.

When the pixel electrode 250 may include or be formed of a multi-layerfilm, in an embodiment, the pixel electrode 250 may include a reflectivefilm and a transparent or translucent electrode which is disposed on thereflective film. In an embodiment, the pixel electrode 250 may include areflective film and a transparent or translucent electrode which isdisposed beneath the reflective film. In an embodiment, for example, thepixel electrode 250 may have a three-layer structure of indium tinoxide/Ag/indium tin oxide (ITO/Ag/ITO), but the invention is not limitedthereto.

Here, the transparent or translucent electrode may contain at least onematerial selected from indium tin oxide (“ITO”), indium zinc oxide(“IZO”), zinc oxide (ZnO), indium oxide (In₂O₃), indium gallium oxide(“IGO”), and aluminum zinc oxide (“AZO”).

A pixel defining film 260 may be disposed on the pixel electrode 250.The pixel defining film 260 includes an opening for exposing at least apart of the pixel electrode 250. The pixel defining film 260 may includean organic material or an inorganic material. In an embodiment, thepixel defining film 260 may include a material such as a photoresist, apolyimide resin, an acrylic resin, a silicone compound or a polyacrylicresin.

The organic light emitting layer 270 may be disposed on the pixelelectrode 250 and the pixel defining film 260. More specifically, theorganic light emitting layer 270 may be disposed on a region of thepixel electrode 250, the region being exposed through the opening of thepixel defining film 260. In an embodiment, the organic light emittinglayer 270 may cover at least a part of the sidewall of the pixeldefining film 260 which defines the opening therein.

In an embodiment, the organic light emitting layer 270 may emit one ofred light, blue light and green light. In another embodiment, theorganic light emitting layer 270 may emit white light, or may emit oneof cyan light, magenta light and yellow light. When the organic lightemitting layer 270 emits white light, the organic light emitting layer270 may include a white light emitting material, or may have a laminatedstructure of a red light emitting layer, a green light emitting layerand a blue light emitting layer to emit white light.

A common electrode 280 may be disposed on the organic light emittinglayer 270 and the pixel defining film 260. In an embodiment, the commonelectrode 280 may be disposed or formed entirely on the organic lightemitting layer 270 and the pixel defining film 260. That is, the commonelectrode 280 may be disposed common to each of the organic lightemitting layer 270 and the pixel defining film 260. In an embodiment,the common electrode 280 may be a cathode electrode of the organic lightemitting diode OLED. In an embodiment, the common electrode 280 mayinclude at least one material selected from Li, Ca, Li/Ca, LiF/Al, Al,Ag, and Mg. The common electrode 280 may include or be made of amaterial having a relatively low work function.

In an embodiment, the common electrode 280 may be a transparent ortranslucent electrode including at least one material selected fromindium tin oxide (“ITO”), indium zinc oxide (“IZO”), zinc oxide (ZnO),indium oxide (In₂O₃), indium gallium oxide (“IGO”), and aluminum zincoxide (“AZO”).

The pixel electrode 250, the organic light emitting layer 270 and thecommon electrode 280 may together constitute an organic light emittingdiode OLED. However, the invention is not limited thereto, and theorganic light emitting diode OLED may have a multi-layer structureincluding a hole injection layer (“HIL”), a hole transporting layer(“HTL”), an electron transporting layer (“ETL”), and an electroninjection layer (“EIL”).

An encapsulation layer 300 may be disposed on the common electrode 280.The encapsulation layer 300 may reduce or effectively prevent water andair from outside the display panel PA from penetrating the organic lightemitting diode OLED. In an embodiment, the encapsulation layer 300 mayinclude a first inorganic layer 301, an organic layer 302, and a secondinorganic layer 303.

The first inorganic layer 301 may be disposed on the common electrode280. The first inorganic layer 301 may include at least one materialselected from silicon oxide (SiOx), silicon nitride (SiNx) and siliconoxynitride (SiONx).

The organic layer 302 may be disposed on the first inorganic layer 301.The organic layer 302 may include any one material selected from epoxy,acrylate and urethane acrylate. The organic layer 302 may planarize thestep difference caused by the pixel defining film 260.

The second inorganic layer 303 may be disposed on the organic layer 302.The second inorganic layer 303 may include at least one materialselected from silicon oxide (SiOx), silicon nitride (SiNx) and siliconoxynitride (SiONx).

Although it is shown in FIG. 5 that each of the first inorganic layer301, the organic layer 302 and the second inorganic layer 303 are each asingle layer, the invention is not limited thereto. That is, at leastone of the first inorganic layer 301, the organic layer 302 and thesecond inorganic layer 303 may be formed to have a multi-layerstructure.

In another embodiment, the encapsulation layer 300 may include ahexamethyldisiloxane (“HMDSO”) layer. More specifically, theencapsulation layer 300 may include the first inorganic layer 301, thesecond inorganic layer 303 and the HMDSO layer disposed between thefirst inorganic layer 301 and the second inorganic layer 303. That is,the above-described organic layer 302 may be replaced by the HMDSOlayer.

In an embodiment of a method of manufacturing a display device, theHMDSO layer may be formed using the same process chamber after the firstinorganic layer 301 is formed. Thus, a process of forming theencapsulation layer 300 may be simplified. The encapsulation layer 300may include the HMDSO layer capable of absorbing stress to havesufficient flexibility.

In an embodiment, the encapsulation layer 300 may be formed asindependent members respectively corresponding to each of the pluralityof display units 600 or may be integrally formed with each of theplurality of display units 600, such that a single encapsulation layer300 to commonly covers all of the plurality of display units 600.

In an embodiment, on the encapsulation layer 300 may be further providedfunctional layers such as a protective layer (not shown) for protectingthe organic light emitting diode OLED and/or a touch sensing layer (notshown).

In an embodiment, the display unit 600 indicated in FIG. 4 may includethe organic light emitting diode OLED and the switching element TR2along with the various layers 101 through 300 shown in FIG. 5. Suchcollection of elements and layers may be disposed on a base substrate ofthe display panel PA, without being limited thereto. The display unit600 may include a light emitting region, such as at the opening in thepixel defining film 260, without being limited thereto. In anembodiment, the base substrate of the display panel PA may be disposedbelow the layers shown in FIG. 5, without being limited thereto.

Referring again to FIG. 3, the normal display area NA may be disposedinside the stretchable display area STA in the top plan view. That is,the stretchable display area STA may be disposed to surround the outerperiphery of the normal display area NA. The stretchable display areaSTA may be disposed closer to an outer edge of the overall display panelPA than the normal display area NA. The stretchable display area STA maybe disposed at each side of the display panel PA as illustrated in FIG.3, without being limited thereto. In an embodiment, the stretchabledisplay area STA may be disposed at less than all sides of the displaypanel PA.

The normal display area NA may include a normal substrate. A normalsubstrate may be defined as a portion of the display panel PA which lessdeformable or less restorable to an original form after a forced appliedthereto. The normal substrate portion of the display panel PA may haveless flexibility than the stretchable substrate portion. Unlike thestretchable substrate STS, the normal substrate may have a uniform plateshape over the entire surface thereof.

A plurality of pixels is arranged on the normal substrate, and each ofthe pixels may include at least one organic light emitting diode. Thepixels on the normal substrate in the normal display area NA may bedriven to generate and/or emit light to display an image.

The normal substrate may have a substantially same basic structure thestretchable substrate STS, except that a pattern including the island101, the bridge 103 and the empty space V is further included or formedat the stretchable substrate STS. That is, FIG. 5 may be a view showinga cross-section of one pixel formed on a normal substrate if only theisland 101 is replaced by the normal substrate. In an embodiment, thenormal substrate at the normal display area NA includes the common basesubstrate of the display panel PA, excluding the island 101, the bridge103 and the empty space V, while the stretchable substrate STS includesthe common base substrate of the display panel PA having the island 101,the bridge 103 and the empty space V.

As described above, when the display area DA includes the stretchabledisplay area STA having relatively high flexibility, the transfercapability of sound caused by the vacuum provided from the vibrationmember 50 can be improved. That is, the flexibility of the stretchabledisplay area STA can reduce the vibration width of the normal displayarea NA (e.g., along the thickness direction of the display device).Since the degree of freedom of movement of the normal display area NAincreases, the transfer of sound through vibration can be made easier.That is, the sound provided from the vibration member 50 can betransferred within the display device and to a user without loss.

Although it is shown in FIG. 3 that the display area DA includes thestretchable display area STA and the normal display area NA, the rangeof the stretchable display area STA is not limited thereto.

In another embodiment, the non-display area NDA may also havestretchable characteristics. The non-display area NDA may also includethe above-described stretchable substrate STS. In this case, theflexibility of the non-display area NDA may be substantially the same asthe flexibility of the stretchable display area STA.

The cover window CW may be disposed on the display panel PA.

The cover window CW may include or be made of transparent glass orplastic. That is, the cover window CW may include a light-transmissivematerial.

The cover window CW may include a central portion CP and a peripheralportion PP. Details thereof will be described with reference to FIG. 6.

FIG. 6 is a partial top plan view of a display device according to theinvention. FIG. 6 shows the cover window CW relative to a portion of thedisplay panel PA. The bracket BC of the display device in FIGS. 1 and 2are omitted for convenience of explanation.

The cover window CW may include the central portion CP and theperipheral portion PP which is disposed to surround the outer peripheryof the central portion CP.

In an embodiment, the peripheral portion PP may have relatively higherflexibility than the central portion CP.

In order for the peripheral portion PP to have higher flexibility thanthe central portion CP, in an embodiment, the central portion CP mayinclude or be made of a relatively rigid material having relatively lowflexibility, and the peripheral portion PP may include or be made of arelatively soft material having relatively high flexibility.

In an embodiment, for example, the central portion CP may include or bemade of glass, and the peripheral portion PP may include or be made ofplastic, silicone, or a polymer material having elasticity.

An example of the polymer material having elasticity may includepolydimethylsiloxane (“PDMS”). However, this is illustrative, and thepolymer material having elasticity is not limited thereto.

When the peripheral portion PP has relatively high flexibility, themovement of the relatively rigid/low flexibility central portion CP dueto the vibration transferred through the vibration member 50 isrelatively reduced. That is, the flexibility of the peripheral portionPP at an outside edge of the display device can help a user not feel thetransferred vibration.

In one or more embodiment of the display device, the quality of soundtransferred through vibration can be improved. The reason for this isthat the degree of freedom of movement of the central portion CP isimproved due to the flexibility of the peripheral portion PP. That is,the improvement of degree of freedom of movement of the central portionCP exhibits a similar effect to an increase in size of a sound box, andthus sound provided from the vibration member 50 may be clearlytransferred to a user.

Referring to FIG. 2 again, the peripheral portion PP having higherflexibility than the central portion CP may overlap the stretchabledisplay area STA of the display panel PA. In this case, an inner sidesurface or edge of the stretchable display area STA and an inner sidesurface or edge of the peripheral portion PP may be aligned with eachother.

Like this, when the peripheral portion PP and the stretchable displayarea STA of the display panel PA, each having relatively highflexibility, overlap each other, the vibration width (e.g., in thethickness direction of the display device) of the normal display area NAand the central portion CP, each having relatively low flexibility, maybe made small. Therefore, the degree of vibration recognized by the usermay decrease or become zero. In addition, the degree of freedom ofmovement of the central portion CP and the normal display area NAincreases, so as to improve the transfer capability of sound throughvibration.

That is, the improvement in degree of freedom of movement of the normaldisplay area NA and the central portion CP can provide better callquality to the user.

FIG. 7 is a partial top plan view of a display unit of a display deviceaccording to the invention. FIG. 8 is a partial top plan view of amodified embodiment of a display unit of a display device according tothe invention.

In an embodiment, a plurality of organic light emitting diodes OLEDs maybe disposed on a single one of the display unit 600. That is, as shownin FIG. 7, the display unit 600 may include an organic light emittingdiode OLED for emitting red light (R), an organic light emitting diodeOLED for emitting blue light (B) and an organic light emitting diodeOLED for emitting green light (G). Although it is shown in FIG. 7 thatthe organic light emitting diodes OLEDs are arranged in order of R, Gand B, the arrangement of the organic light emitting diodes OLEDs is notlimited thereto. That is, the plurality of organic light emittingelements OLEDs may be arranged as shown in FIG. 8, or may be arranged ina pentagonal shape or structure or a honeycomb shape or structure.

Hereinafter, a display device according to other embodiments of theinvention will be described. Some of the components to be describedbelow may be substantially the same as the components having beendescribed in one or more of the previously-described embodiments of thedisplay device according to the invention. Descriptions of somecomponents may be omitted to avoid duplicate descriptions. FIGS. 9through 12 may be views taken along line I-I′ of FIG. 1.

FIG. 9 is a cross-sectional view of another embodiment of a displaydevice according to the invention.

Referring to FIG. 9, in an embodiment, a second adhesive layer AD2 maybe interposed between the cover panel 500 and bracket BC.

The second adhesive layer AD2 may be disposed or formed on the entireback surface of the cover panel 500 excluding an area where thevibration member 50 is inserted.

Accordingly, the second adhesive layer AD2 may attach the cover panel500 to the bracket BD.

In an embodiment, the second adhesive layer AD2 may include aphotocurable resin or a thermosetting resin having relatively hightransmittance and adhesive performance. In an embodiment, for example,the second adhesive layer AD2 may be obtained by applying a resin suchas an acrylic resin to the cover panel 500 and/or the bracket BD, andthen curing the applied resin by irradiating light such as ultraviolet(UV) light.

In an embodiment, the second adhesive layer AD2 may include apressure-sensitive adhesive (“PSA”) such as in a tape form.

In an embodiment, the second adhesive layer AD2 may include an opticallyclear adhesive (“OCA”) such as in a tape form.

In an embodiment, a thickness of the second adhesive layer AD2 may beabout 10 micrometers (μm) to about 20 μm.

FIG. 10 is a cross-sectional view of a modified embodiment of a displaydevice according to the invention.

Referring to FIG. 10, a second adhesive layer AD2_1 may be disposed on apartial portion of the back surface of the cover panel 500. That is,unlike that shown in FIG. 9, the second adhesive layer AD2_1 may beformed at partial portions of the back surface of the cover panel 500excluding an area where the vibration member 50 is inserted. The secondadhesive layer AD2_1 may be provided in plurality spaced apart from eachother.

FIG. 11 is a cross-sectional view of still another embodiment of adisplay device according to the invention.

Referring to FIG. 11, in a display device according to this embodiment,each of a cover window CW and a display panel PA2 may include a flatportion having a flat upper surface, and a bent portion which isdisposed at both of opposing sides of the flat portion and having acurved shape with a curvature.

In an embodiment, the flat portion WF of the cover window CW may overlapthe flat portion PF of the display panel PA2, and the bent portion WB ofthe cover window CW may overlap the bent portion PB of the display panelPA2.

In an embodiment, the flat portion WF of the cover window CW may be acentral portion CP, and the bent portion WB of the cover window CW maybe a peripheral portion PP1. That is, the bent portion WB of the coverwindow CW may have a shape curved along at least one curvature. Asdescribed above, since the flexibility of the peripheral portion PP1 ishigher than the flexibility of the central portion CP, the flexibilityof the bending portion WB of the cover window CW may be higher than theflexibility of the flat portion WF thereof.

In an embodiment, the flat portion PF of the display panel PA2 mayinclude a normal display area NA, and the bent portion PB of the displaypanel PA2 may include a stretchable display area STA1 and a non-displayarea NDA1.

That is, the stretchable display area STA1 and the non-display area NDA1disposed at both of opposing sides of the normal display area NA mayhave a shape curved along at least one curvature.

When the cover window CW and the display panel PA2 have bent portions asdescribed above, a cover panel 501 may have bent portions at both ofopposing sides of a flat portion thereof.

FIG. 12 is a cross-sectional view of yet another embodiment of a displaydevice according to the invention.

Referring to FIG. 12, a display device according to this embodiment mayinclude a first display panel PA_1 including a stretchable display areaSTA_1 and a first dummy area DS, a second display panel PA_2 including anormal display area NA and a second dummy area DU, and a cover windowsCW including a peripheral portion PP and a central portion CP. Thesecond display panel PA_2 is disposed closed to a viewing side of thedisplay device than the first display panel PA_1.

In an embodiment, the first display panel PA_1 may include thestretchable display area STA_1 and the first dummy area DS. Thestretchable display area STA_1 of the second display panel PA_2 may besubstantially the same as the stretchable display area described abovein one or more embodiment of the display device according to theinvention.

The stretchable display area STA_1 may be disposed to surround the outerperiphery of the first dummy area DS in a top plan view. In anembodiment, the stretchable display area STA_1 of the first displaypanel PA_1 may have relatively higher flexibility than the normaldisplay area NA of the second display panel PA_1. For this purpose, asdescribed above, the stretchable display area STA_1 may include astretchable substrate STS.

The first dummy area DS of the first display panel PA_1 may overlap thenormal display area NA of the second display panel PA_2. In anembodiment, the first dummy area DS may have substantially the sameplanar area as the normal display area NA in the top plan view.

Since an image is displayed at the normal display area NA of the seconddisplay panel PA_2, the first dummy area DS of the first display panelPA_1 overlapping the normal display area NA in the top plan view, maynot display an image. That is, the first dummy area DS may have nofunction except for compensating a step difference within the displaydevice.

In an embodiment, the first dummy area DS of the first display panelPA_1 may include a stretchable substrate STS in the same manner as thestretchable display area STA_1.

The second display panel PA_2 may be disposed on the first display panelPA_1, to be closer to the cover window CW than the first display panelPA_1.

The second display panel PA_2 may include the normal display area NA andthe second dummy area DU. The normal display area NA of the seconddisplay panel PA_2 may be substantially the same as that described abovein one or more embodiment of the display device according to theinvention. The second dummy area DU of the second display panel PA_2 maybe disposed outside the normal display area NA in a top plan view. Thesecond dummy area DU of the second display panel PA_2 may overlap thestretchable display area STA_1 of the underlying first display panelPA_1, and may have substantially the same planar size as the stretchabledisplay area STA_1 in the top plan view.

In an embodiment, the second dummy area DU of the second display panelPA_2 may have optical transparency. Accordingly, the image generated inthe stretchable display area STA_1 may be provided to a user through theoptically transparent second dummy area DU.

In an embodiment, the second dummy area DU may include or be made of anelastic material for step difference compensation. In this case, thesecond dummy area DU may include or be made of a polymer material havingelasticity. In an embodiment, the second dummy area DU may haverelatively higher flexibility than that of the normal display area NA.

The second dummy area DU may overlap the peripheral portion PP of thecover window CW. That is, the peripheral portion PP of the cover windowCW, the second dummy area DU of the second display panel PA_2, and thestretchable display area STA_1 of the first display panel PA_1 mayoverlap one another in the top plan view. Thus, as described above, whenconsidering the entire display device in FIG. 12, the flexibility of theedge portion thereof (e.g., at the peripheral portion PP, the seconddummy area DU and the stretchable display area STA_1) may be made higherthan the flexibility of the middle portion thereof (e.g., at centralportion CP, the normal display area NA and the first dummy area DS).When the flexibility of the edge portion of a display device is higherthan the flexibility of the middle portion thereof, as described above,the sound provided from the vibration member 50 may be transferred to auser without loss while reducing a degree of the vibration recognized bythe user.

Although FIG. 12 does not show a non-display area (NDA in FIG. 3), in anembodiment, a non-display area of the second display panel PA_2 may beincluded within the second dummy area DU.

In another embodiment, the non-display area of the second display panelPA_2 may be disposed between the second dummy area DU and the normaldisplay area NA.

Although FIG. 12 illustrates a case where the second display panel PA_2is disposed on the first display panel PA_1 to be closer to the coverwindow CW, the stacking order of both of them is not limited thereto. Inanother embodiment, the first display panel PA_1 may be disposed on thesecond display panel PA_2 to be closer to the cover window CW.

As described above, according to one or more embodiment of theinvention, call quality is improved.

Further, sound transfer capability through vibration is improved toimprove the call quality using the sound transfer.

The effects of the invention are not limited by the foregoing, and othervarious effects are anticipated herein.

Although embodiments of the invention have been disclosed forillustrative purposes, those skilled in the art will appreciate thatvarious modifications, additions and substitutions are possible, withoutdeparting from the scope and spirit of the invention as disclosed in theaccompanying claims.

What is claimed is:
 1. A display device, comprising: a cover windowthrough which an image is displayed, including a central portion and aperipheral portion which is disposed closer to an outer edge of thedisplay device than the central portion; a first display panel withwhich an image is displayed, including: a first dummy area correspondingto the central portion of the cover window, and a first display area atwhich the image of the first display panel is displayed and at which thefirst display panel is flexible, the first display area disposed closerto the outer edge of the display device than the first dummy area; and asecond display panel with which an image is displayed, including: asecond display area corresponding to the first dummy area of the firstdisplay panel and at which the image of the second display panel isdisplayed, and a second dummy area disposed corresponding to the firstdisplay area of the first display panel, the second dummy area disposedcloser to the outer edge of the display device than the second displayarea, wherein the flexibility of the first display area of the firstdisplay panel is greater than that of the second display area of thesecond display panel, and flexibility of the peripheral portion of thecover window is greater than that of the central portion of the coverwindow.
 2. The display device of claim 1, wherein the second dummy areaof the second display panel which corresponds to the first display areaof the first display panel has optical transparency and includes anelastic material.
 3. The display device of claim 1, wherein the seconddummy area of the second display panel, the first display area of thefirst display panel and the peripheral portion of the cover window aredisposed at a same outer edge of the display device and overlap oneanother along a thickness direction of the display device.
 4. Thedisplay device of claim 1, wherein the first dummy area of the firstdisplay panel has a same planar area as that of the second display areaof the second display panel.
 5. The display device of claim 1, whereinthe first display area of the first display panel includes: an islandprovided in plurality spaced apart from each other, and a bridgeprovided in plurality respectively connecting the plurality of islandsto each other, the bridge being stretchable.
 6. The display device ofclaim 1, wherein the first display area of the first display panelfurther includes a display unit with which the image of the firstdisplay panel is generated, the display unit including an organic lightemitting diode, wherein the display unit including the organic lightemitting diode is disposed on the island of the stretchable displayarea.
 7. A display device, comprising: a display panel including adisplay area at which an image is displayed, the display area comprisinga first display area and a second display area including a display unitwith which the image is generated, the first display area disposed moreinward from the outer edge of the display device than the second displayarea, a cover window disposed on a first surface of the display panel,and including a peripheral portion and a central portion which is moreinward from the outer edge of the display device than the peripheralportion; a bracket disposed on a second surface of the display panelwhich is opposite to the first surface of the display panel; and avibration unit which transfers sound through vibration, the vibrationunit overlapping the first display area along a thickness direction ofthe display device, wherein the vibration unit is disposed on a secondsurface of the display panel, and wherein a gap exists between thesecond surface of the display panel and the bracket.
 8. The displaydevice of claim 7, further comprising a first adhesive layer interposedbetween the peripheral portion of the cover window and the bracket. 9.The display device of claim 8, wherein the first adhesive layer isdisposed an edge of the bracket.
 10. The display device of claim 7,wherein the bracket includes an accommodation portion in which thevibration unit is disposed.
 11. The display device of claim 10, whereinat least a portion of the bracket is removed in the accommodationportion.
 12. The display device of claim 7, wherein the central portionof the cover window corresponds to a flat portion, and the peripheralportion of the cover window corresponds to a bent portion having acurved shape with a curvature.
 13. The display device of claim 12,wherein a flexibility of the peripheral portion is higher than aflexibility of the flat portion.
 14. The display device of claim 12,wherein a flexibility of the second display area is higher than aflexibility of the first display area.
 15. The display device of claim14, wherein the flat portion overlaps the first display area in athickness direction of the cover window, and the bent portion overlapsthe second display area in the thickness direction of the cover window.16. The display device of claim 15, wherein the display panel furtherincludes a non-display area overlapping the bent portion, and the seconddisplay area is disposed more inward from the outer edge of the displaydevice than the non-display area.
 17. The display device of claim 11,further comprising a first adhesive layer interposed between the bentportion of the cover window and the bracket.
 18. The display device ofclaim 7, wherein the vibration unit includes a piezo material.
 19. Thedisplay device of claim 7, further comprising: a cover panel disposed onthe first surface of the display panel, wherein the cover panel does notoverlap the vibration unit in a thickness direction of the cover panel.20. The display device of claim 19, wherein a gap exists between thecover panel and the bracket.